July 20, 2006

Adult mosquito trap information from the week of July 9 indicates the numbers of Culex tarsalis mosquitoes in southern Manitoba were similar to the numbers from the week of July 2.

Samples collected during the week of July 9 from the Town of Boissevain in the Assiniboine Regional Health Authority indicate a small number of infected Culex tarsalis mosquitoes. Adult mosquito control has not been recommended at this time.

Preliminary trap information from the week of July 16 indicates the Culex tarsalis numbers in many southern Manitoba communities are increasing compared to the numbers from the week of July 9. Heat is one factor that affects the development of Culex tarsalis mosquitoes and Culex tarsalis activity increases when the average daily temperature is above 16 C.

This year, positive mosquito samples have been found in four Manitoba communities: Selkirk, Carman, Steinbach and Boissevain. The province continues to monitor adult Culex tarsalis mosquito numbers in these communities and across southern Manitoba.

Testing for West Nile virus is ongoing at Cadham Provincial Laboratory. Weekly average trap counts of Culex tarsalis by regional health authority are available on the province’s West Nile virus website at http://www.gov.mb.ca/health/wnv.

The risk of becoming ill from West Nile virus is rising and will continue to increase in the coming weeks. To date, no human cases of WNV have been identified in Manitoba.

Manitobans can reduce the risk of mosquito bites by:

• reducing the amount of time spent outdoors during peak mosquito hours between dusk and dawn,

• using appropriate mosquito repellent, and

• wearing light-coloured, loose-fitting clothing.

Manitobans can reduce the number of Culex tarsalis mosquitoes around their home by reducing standing water. This includes:

• regularly cleaning and emptying eavestroughs, bird baths and other items that might collect water;

• ensuring rain barrels are covered with mosquito screening or are tightly sealed around the downspout;

• making sure yards are clear of old tires or other debris that collect water; and

• making sure doors and window screens fit tightly and are free of holes.

For more information about West Nile virus, contact Health Links–Info Santé at 788-8200 or
1-888-315-9257 or visit the Manitoba Health website at http://www.gov.mb.ca/health/wnv.

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